Is biomass really a renewable fuel?

Posted onFebruary 19, 2013byCharlotte

The woody biomass used for heating can come from woodland trees or fast growing tree crops like this one

In simple terms, biomass is defined as a renewable fuel source because the term ‘renewable’ means that it can be relatively easily replaced, and biomass fuel can. The biomass burnt as a heating fuel is usually a wood product of some kind, and trees regrow fairly quickly, especially if you select a fast growing species. Even though it takes a number of years for the tree to regrow, this is considered ‘quick’ when compared with the hundreds of thousands of years it takes for coal, oil and gas to form. So we think of biomass as a ‘renewable’ fuel, and coal, oil and gas as ‘non-renewable’ fuels.

People can get confused about the relative environmental merits of coal vs. biomass when it’s mentioned that twice as much biomass as coal has to be burnt to achieve the same level of heat. This is true, and is to do with energy density. Coal is about twice as energy dense as wood, meaning that you do have to burn twice as much wood to get the same level of heat. But this doesn’t mean that there’s a danger that burning biomass produces more carbon emissions than burning coal – in fact, for every unit of energy produced biomass produces 95% fewer carbon emissions than coal over the lifecycle of the fuel’s production and use¹. This is because the energy density of a fuel has little to do with how much carbon it will emit when burnt. So despite needing twice as much fuel, biomass really is a greener option than coal and other non-renewables.